Number Server - Ben Coffey
A REST-like service offering a variety of data for decimal and binary numbers: enter a number and get its sine, cosine, tangent, natural logarithm, square root, square, cube, binary, hexadecimal, octal, the single-digit sum of the digits, and more. Output
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Numbers - Kirsten Silverman
Blog by a Massachusetts middle school math teacher who "loves number theory and thinks sixth grade is the perfect place to share this." Posts, which date back to August, 2012, have included "Flipping"; "Cogs"; "LCM, GCF, and Fractions"; "Ordering Fractions";
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Number Strings - Imm, Kara; Lambert, Rachel; et al.
A place to find new strings, post strings, get feedback on design or number choice, and discuss the pedagogy of number strings, a classroom routine based on "sets of related math problems, crafted to support students to construct big ideas about mathematics
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Number World - David Geistert
Key in any positive integer less than 10^15 and press the "Look up" button for properties about it: factorization, divisors, cross sum, equivalence in multiple bases, and more. Number World's math tools include an equation solver, an equation system solver,
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NUMDRUM - John T. Harrison
The "Numdrum" helps children understand addition, subtraction, and other fundamental arithmetic concepts. An alternative to the number line and the 10 x 10 number square, this "decimal helical number line" lists integers around a tube, ten to a turn,
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Numeracy Works - David Hartmann, Numeracy Works LLC
Numeracy Works is a commercial software company which sells Tabula, a new tool for math education. Use Tabula to create, construct, cut, tape, fold, and transform. Make fold patterns, tiling patterns, tessellations, and perspective drawings. Also on
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Numericana.com - Gérard P. Michon
The online companion of Numericana, this site contains excerpts from Michon's book, including the entire glossary of scientific terms. Browse an index with pithy summaries, browse by popularity, or search nearly two hundred of his "final answers" of readers'
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Numm˛lt - Maurici Carbˇ Jordi
Java applets: an area "workshop," which explains area and division by converting numbers in area units; an architect's toy blocks, with gravity; connecting and programming elementary logic (in the form of pipes with light bulbs signifying true sentences);
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Odd Day - Ron Gordon
Mathematical observations, original musings, news coverage, and cartoons in celebration of January 3, 2005 (1/3/5), July 9, 2011 (7/9/11), and other times when three consecutive odd numbers make up the date. Gordon, retired from teaching high school in
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Off The Hypotenuse - Glenn Kenyon
Kenyon started this blog in pursuit of "a good discussion of resources, ideas, and innovative ideas for teachers of Algebra." Humorous videos, comic strips, and posts, which date back to March of 2007, have included "Math Lessons learned from Karate,"
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Ohio Literacy Resource Center - Kent State University
The Ohio Literacy Resource Center provides support, training and resources for the people who work in and attend classes at adult and family literacy programs. The OLRC also works with GED graduates who are attending Kent State University. The site offers
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Old and New Arithmetic - Ivars Peterson (MathLand)
"Three merchants have invested their money in a partnership..." This problem appears in a mathematics textbook known as the Treviso Arithmetic. The original book, written in a Venetian dialect, had no formal title, and its author is unknown. Treviso is
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Oliver Knill
Research, teaching, and media by this preceptor in Harvard's math department. Knill began in dynamical systems, tackling first ergodic and spectral theoretical questions, then probability theory and elementary number theory. This led to his "passion for
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Omni Calculator - Piotr Malek
Freely offering calculator apps, as well as the code for calculators to customize and embed in your own website. Calculators for math applications include roots and exponents, percentages, proportions, distances in two and three dimensions, and several
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one good thing
Blog by a group of "dedicated, fascinated, hard-working, inspiring" secondary teachers who believe that "every day may not be good, but every day there is (at least) one good thing worth sharing. Here are our stories." Posts, which date back to January,
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One on Epsilon - One on Epsilon Pty Ltd
Blog of "exploratory, curiosity-driven mathematics." Posts, which date back to October, 2016, have included "Designing Square Root Marbles for iOS"; "The Number Game and the Silent Version"; "All, None and Forever"; "A Formula for the Personality of a
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One, Two.. Infinity - Marian Small
PDFs of presentations from the professional development consultant and author of Making Math Meaningful to Canadian Students K-8, More Good Questions: Great Ways to Differentiate Secondary Mathematics Instruction (9 - 12), Eyes on Math: A Visual Approach
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